The present invention relates to press machines of the type that may be used for dough presses and to apply heat transfer designs to clothing or other articles.
Hand operated press machines have long been used for a variety of different applications. In food preparation applications such presses may be used to press balls of dough into the shape of a pizza crust or other desired shapes, as may be dictated by the construction of the upper and lower platens. As the press is operated, a movable upper platen is typically brought downward towards the stationary lower platen, compressing a product there-between. The upper platen is typically coupled to a mechanism allowing the user to pull down on a handle to bring the two platens to proximate engagement. The force applied to the product is typically dictated by the downward force that is manually applied to a handle mechanism, for so long as the operator continues to apply that force.
While such contemporary systems operate effectively, the continuous use of such mechanisms may be physically demanding upon the operator, due to the need to exert continual force upon the handle as the product is compressed between the upper and lower platens. For example, when a dough product is being compressed the physical characteristics of the dough are such that flattening takes place slowly as the compression force is maintained. As an operator maintains the compressive force on the dough the platens slowly move together as the dough spreads outward.
As many companies realize, redundant physical stress upon the operator may give rise to safety concerns, as well as raise quality control issues respecting the consistency of the resultant product. While automatic presses are available that do not require manual pressing, such devices are typically expensive to purchase and operate, and do not provide the regulation available from manual presses. Moreover, such automatic devices may give rise to safety concerns inherent in the operation of automatic machinery.
Accordingly, there is a need to provide a manually operated press mechanism that mitigates or eliminates the requirement to manually maintain a compressive force upon the handle mechanism as the product is compressed between the upper and lower platens.
More particularly, in order to avoid operator stress it is therefore desirable to provide a press machine wherein the compressive force may be initially applied manually by the operator though mechanically maintained by the press mechanism independent of operator effort. It is further desirable to allow for a variation of the force level that is maintained by the mechanism after the operator applies the initial force and releases the handle mechanism.
Yet another short-coming of existing press machines concerns difficulties that may arise in releasing the platens from compression. When compressed, certain products, such as dough, create suction which holds the platens together and opposes efforts to release the platens from the compressed position. Consequently, the operator of contemporary dough presses may not only be strained by the need to manually maintain downward pressure upon the dough as it is formed, but may be additionally strained by the need to apply considerable upward force to overcome the suction caused by pressing operation as the platens are separated from one another. Accordingly, it would be desirable to additionally provide a means for mitigating the operator effort necessary to separate the platens after the product is compressed. Preferably, such means would be adjustable to settings appropriate for the product being compressed and would not interfere in the press operation when products are compressed.
These and other objects and advantages are addressed by the present invention as described in connection with the illustrated embodiments. It is to be understood, however, that the foregoing description and accompanying illustrations are intended as exemplary of various implementations of the present invention and are not limiting in relation alternate implementations consistent with the broader aspects of the invention.
A pressing device is disclosed including a housing, a lower engaged to that housing and adapted to receive products to be pressed and an upper platen engaged to the housing and manually translatable with respect to the lower platen. A handle mechanism is connected to the upper platen for translating the upper platen with respect to the lower platen. The handle mechanism includes a resilient over-center locking mechanism for translating the upper platen to a locked position proximate the lower platen, whereupon the upper platen is further translated towards the lower platen independent of manual force.
In the presently preferred embodiment the pressing device includes at least one resilient compression member connected to the over-center locking mechanism an operative to urge towards the lower platen at a substantially constant compressive force. The resilient compression member may be comprised as a pair of springs.
The handle mechanism may further comprise an adjustment mechanism, connected to the resilient compression member, for adjusting the operating length of the resilient compression member. The adjustment mechanism may include a stop bar, in abutting engagement with the compression member and translatable within the handle mechanism, to adjust pre-load of the compression member.
At least one resilient mounting member may be provided to connect the lower platen to the housing. The resilient mounting member is deformable to allow the lower platen to translate to a slanted position relative to the upper platen, as the upper platen is moved upwardly therefrom. This relieves suction formed by compression of products between the upper and lower platens, facilitating separation of the platens.
A resilient base securant member may be disposed on the lower surface of the housing to engage a support surface, and to maintain the contacting engagement between the housing and the support surface during separation of the platens.